Global Chemistry and Thermal Structure Models for the Hot Jupiter WASP-43b and Predictions for JWST Olivia Venot, Vivien Parmentier, Jasmina Blecic, Patricio Cubillos, Ingo Waldmann, Quentin Changeat, Julianne Moses, Pascal Tremblin, Nicolas Crouzet, Peter Gao, et al. To cite this version: Olivia Venot, Vivien Parmentier, Jasmina Blecic, Patricio Cubillos, Ingo Waldmann, et al.. Global Chemistry and Thermal Structure Models for the Hot Jupiter WASP-43b and Predictions for JWST. The Astrophysical Journal, American Astronomical Society, 2020, 890 (2), pp.176. 10.3847/1538- 4357/ab6a94. hal-03009572 HAL Id: hal-03009572 https://hal.archives-ouvertes.fr/hal-03009572 Submitted on 19 Nov 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. DRAFT VERSION JANUARY 15, 2020 Typeset using LATEX twocolumn style in AASTeX61 GLOBAL CHEMISTRY AND THERMAL STRUCTURE MODELS FOR THE HOT JUPITER WASP-43b AND PREDICTIONS FOR JWST OLIVIA VENOT,1 VIVIEN PARMENTIER,2 JASMINA BLECIC,3 PATRICIO E. CUBILLOS,4 INGO P. WALDMANN,5 QUENTIN CHANGEAT,5 JULIANNE I. MOSES,6 PASCAL TREMBLIN,7 NICOLAS CROUZET,8 PETER GAO,9 DIANA POWELL,10 PIERRE-OLIVIER LAGAGE,11 IAN DOBBS-DIXON,3 MARIA E. STEINRUECK,12 LAURA KREIDBERG,13, 14 NATALIE BATALHA,15 JACOB L. BEAN,16 KEVIN B. STEVENSON,17 SARAH CASEWELL,18 AND LUDMILA CARONE19 1Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), UMR CNRS 7583, Université Paris-Est-Créteil, Université de Paris, Institut Pierre Simon Laplace, Créteil, France 2AOPP, Department of Physics, University of Oxford 3NYU Abu Dhabi, Abu Dhabi, UAE 4Space Research Institute, Austrian Academy of Sciences, Schmiedlstr. 6, 8042, Graz, Austria 5University College London, Department of Physics and Astronomy, Gower Street, London WC1E 6BT, UK 6Space Science Institute, Boulder, CO, USA 7Maison de la Simulation, CEA, CNRS, Univ. Paris-Sud, UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France 8Science Support Office, Directorate of Science, European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, The Netherlands 9Astronomy Department, University of California, Berkeley, 501 Campbell Hall, MC 3411, Berkeley, CA 94720 10Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA 11AIM, CEA, CNRS, Université Paris-Saclay, Université Paris Diderot, Sorbonne Paris Cité, UMR7158 F-91191 Gif-sur-Yvette, France 12Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ 85719, USA 13Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 14Harvard Society of Fellows, 78 Mount Auburn Street, Cambridge, MA 02138 15Department of Astronomy & Astrophysics, University of California, Santa Cruz, CA 95064, USA 16Department of Astronomy & Astrophysics, University of Chicago, 5640 S., Ellis Avenue, Chicago, IL 60637, USA 17Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 18Dept. of Physics and Astronomy, Leicester Institute of Space and Earth Observation, University of Leicester, University Road,Leicester, LE1 7RH, UK 19Max Planck Institute for Astronomy, Koenigsstuhl 17, D-69117 Heidelberg, Germany ABSTRACT The James Webb Space Telescope (JWST) is expected to revolutionize the field of exoplanets. The broad wavelength coverage and the high sensitivity of its instruments will allow characterization of exoplanetary atmospheres with unprecedented precision. Following the Call for the Cycle 1 Early Release Science Program, the Transiting Exoplanet Community was awarded time to observe several targets, including WASP-43b. The atmosphere of this hot Jupiter has been intensively observed but still harbors some mysteries, especially concerning the day-night temperature gradient, the efficiency of the atmospheric circulation, and the presence of nightside clouds. We will constrain these properties by observing a full orbit of the planet and extracting its spectroscopic phase curve in the 5–12 µm range with JWST/MIRI. To prepare for these observations, we performed an extensive arXiv:2001.04759v1 [astro-ph.EP] 14 Jan 2020 modeling work with various codes: radiative transfer, chemical kinetics, cloud microphysics, global circulation models, JWST simulators, and spectral retrieval. Our JWST simulations show that we should achieve a precision of 210 ppm per 0.1 µm spectral bin on average, which will allow us to measure the variations of the spectrum in longitude and measure the night-side emission spectrum for the first time. If the atmosphere of WASP-43b is clear, our observations will permit us to determine if its atmosphere has an equilibrium or disequilibrium chemical composition, providing eventually the first conclusive evidence of chemical quenching in a hot Jupiter atmosphere. If the atmosphere is cloudy, a careful retrieval analysis will allow us to identify the cloud composition. 2 VENOT ET AL. Keywords: methods: numerical — planets and satellites: atmospheres — planets and satellites: composition — planets and satellites: gaseous planets — planets and satellites: individual (WASP-43b) — tech- niques: spectroscopic WASP-43b modelling 3 1. INTRODUCTION man 2016), high metallicity (Kataria et al. 2015), disequi- Giant planets that orbit very close to their host stars — librium chemistry (Mendonça et al. 2018b) or the presence so-called “hot Jupiters” — are expected to be tidally locked, of clouds (Kataria et al. 2015) were proposed to explain this with one hemisphere constantly facing the star, and one mystery. hemisphere in perpetual darkness. The uneven stellar irra- The James Webb Space Telescope (JWST) is expected to diation incident on such planets leads to strong and unusual transform our understanding of the complexity of hot Jupiters radiative forcing, resulting in large temperature gradients and atmospheres thanks to the numerous observations of transit- complicated atmospheric dynamics. The atmospheric com- ing hot Jupiters it will perform. Rapidly after the launch and position and cloud structure on these planets can, in turn, commissioning of the JWST, exoplanet spectra will be ob- vary in three dimensions as the temperatures change across tained in the framework of the Transiting Exoplanet Com- the globe, and as winds transport constituents from place to munity Early Release Science (ERS) Program (Bean et al. place. Strong couplings and feedbacks between atmospheric 2018). Three hot Jupiters will be observed using the differ- chemistry, cloud formation, radiative transfer, energy trans- ent instruments of the JWST and the data will be available port, and atmospheric dynamics exist to further influence immediately to the community. Among these, WASP-43b atmospheric properties. The inherently non-uniform nature is the nominal target that will be observed during the sub- of these atmospheres complicates derivations of atmospheric program “MIRI Phase Curve”. A full orbit phase curve, cov- properties from transit, eclipse, and phase curve observa- ering two secondary eclipses and one transit, will be acquired tions. Three-dimensional models that can track the relevant with MIRI (Rieke et al. 2015). We will observe WASP-43b physics and chemistry on all scales — both large and small with MIRI during the Cycle 1 ERS Program developed by the distance scales, and large and small time scales — are needed Transiting Exoplanet Community (PIs: N. Batalha, J. Bean, to accurately interpret hot Jupiter spectra. K. Stevenson; Stevenson et al. 2016; Bean et al. 2018). The Discovered in 2011 by Hellier et al.(2011), the hot Jupiter MIRI phase curve is our best opportunity to probe the cooler WASP-43b orbits a relatively cool K7V star (4 520 ± 120 nightside of the planet, determine the presence and composi- K, Gillon et al. 20121). It has the smallest semi-major axis tion of clouds, detect the signatures of disequilibrium chem- of all confirmed hot Jupiters and one of the shortest orbital istry and more precisely measure the atmospheric metallicity. periods (0.01526 AU and 19.5 h respectively, Gillon et al. The MIRI phase curve will be complemented by a NIRSpec 2012). In addition to its exceptionally short orbit, WASP- phase curve (GTO program 1224, Pi: S. Birkmann). The 43b is very good candidate for in-depth atmospheric charac- later will provide a robust estimate of the water abundances terization through transit thanks to its large planet-star radius on the dayside of the planet but will probably not be able to ratio and the brightness of its host star, leading to a very good obtain decisive information about the nightside. MIRI will signal-to-noise ratio. The planet is also a good candidate for observe the planet at longer wavelengths where the thermal eclipse and phase curve observations thanks to the important emission is more easily detectable and provide the first spec- flux ratio between the emission of the star and the exoplanet. trum of the nightisde of a hot Jupiter. Correctly interpreting To date, many observations of the planet’s atmosphere the incoming data will be, however, challenging. As shown have